GB821974A - Improvements relating to guns having gas-operated bolt and carrier systems - Google Patents

Abstract

821,974. Gas-operated firearms. STONER, E. M. May 10, 1957 [Aug. 14, 1956], No 14999/57. Class 119 In an automatic gasoperated firearm, the rotary bolt 25, Fig. 4, is located within a bolt carrier 36 slidable in the receiver 10, the arrangement being- such that limited sliding movement is permitted between the bolt and carrier to effect the locking and unlocking of the bolt, and between the bolt and carrier is defined a chamber 37 into which the explosive gases resulting from firing are conducted directly from the barrel to cause retraction of the carrier 36 and unlocking and subsequent retraction of the bolt 25. As shown in Fig. 4, a gas passage 40 made of two tubes 42, 43 conducts the gas from a barrel port 41 to a port 39 in the receiver 10. In the breech locked position shown this pare 39 registers with a port 38 leading to the chamber 37. The bolt 25 has a projecting pin 34 which engages and travels in a helical .groove 35 in the carrier 36 which is keyed against rotation in the receiver 10. In the breech locked position lugs 31 on the bolt engage behind abutments 32 of the receiver 10. The bolt 25 carries a firing pin 50 which is urged to the co-operative position by a spring 51. On firing and as soon as the chamber 37 is filled with gas at the required pressure, the carrier 36 is driven rearwardly and the port 38 is disconnected from the port 39 as shown in Fig. 5 thus cutting off the supply of gas. At the same time the bolt 25 is caused to rotate and unlock the lugs 32 from the receiver and the bolt and carrier then move rearwardly together. The gas can then escape from the chamber 37 through chamber ports 38, 56 and slots 55, 52 respectively in the receiver. A spring (not shown) returns the carrier and bolt to the initial position. In a modification, Fig. 8, the gas is led from the barrel through a passage 40a into a fitting 71 in the receiver 10a. This fitting 71 forms a sliding fit with the carrier 36a and acts a piston in a cylindrical passage 72 leading to the chamber 37a. A coupling 46, Fig. 2, connects the barrel port 41 with the gas tube 43 and is bolted by a bolt 70 to the stock 2. The coupling serves as a projection whereby the stock 2 may be connected to the barrel 4. A hammer 14 operates the firing pin 50 and a magazine 17 comprising a follower 19 biased by spring 20 is held within the receiver by a locking finger 18.